Looks like a nice start. I haven't verified the behavior yet, but I think it's what we want (any thoughts @wntrblm/nox?). Also, I approved the CI runs to discard any failure.

This is looking good. Although I've checked out your PR and can't seem to get the desired behaviour:

# noxfile.py

@nox.session(tags=["hello"])
def hello(session: nox.Session) -> None:
    """
    Does something.
    """
    session.log("hello")

When I run nox -t hello I get the following:

So not sure what's going on there?

It would also be really good to incorporate the tags somehow into the output of nox --list, although I think that would be better in a fresh PR, let's get the functionality merged first then work on how we show it

# noxfile.py

@nox.session(tags=["hello"])
def hello(session: nox.Session) -> None:
    """
    Does something.
    """
    session.log("hello")

@FollowTheProcess Thanks for reviewing. I tried it with your example and it's working as expected:

$ nox -t hello
nox > Running session hello
nox > Creating virtual environment (virtualenv) using python3.9 in .nox/hello
nox > hello
nox > Session hello was successful.

$ nox -k "hello or other"
nox > Running session hello
nox > Creating virtual environment (virtualenv) using python3.9 in .nox/hello
nox > hello
nox > Session hello was successful.

$ noxpy -k "not hello"
nox > No sessions selected after filtering by keyword.

Thanks @edgarrmondragon! 🎉